public class Author implements Serializable{ 
  private int id; 
 
  private String name; 
 
  //... 
} 

public class Book implements Serializable{ 
  private String title; 
  private Author author; 
  //... 
} 

 Book book=new Book();  
 book.setTitle("Java编程思想");  
 Author author=new Author();  
 author.setId(1);  
 author.setName("Bruce Eckel");  
 book.setAuthor(author);  
 Intent intent=new Intent(this,SecondActivity.class);  
 intent.putExtra("book",book);  
 startActivity(intent); 

 Book book= (Book) getIntent().getSerializableExtra("book"); 
 Log.d(TAG,"book title->"+book.getTitle()); 
 Log.d(TAG,"book author name->"+book.getAuthor().getName()); 

public class Author{ 
  private int id; 
 
  private String name; 
 
  //... 
} 

public class Book{ 
  private String title; 
  private Author author; 
  //... 
} 

Book book=new Book(); 
book.setTitle("Java编程思想"); 
Author author=new Author(); 
author.setId(1); 
author.setName("Bruce Eckel"); 
book.setAuthor(author); 
Intent intent=new Intent(this,SecondActivity.class); 
intent.putExtra("book",new Gson().toJson(book)); 
startActivity(intent); 

String bookJson=getIntent().getStringExtra("book"); 
Book book=new Gson().fromJson(bookJson,Book.class); 
Log.d(TAG,"book title->"+book.getTitle()); 
Log.d(TAG,"book author name->"+book.getAuthor().getName()); 

public class Author implements Parcelable{ 
  private int id; 
 
  private String name; 
 
  //setter & getter... 
 
  @Override 
  public int describeContents() { 
 
    return 0; 
  } 
 
  @Override 
  public void writeToParcel(Parcel dest, int flags) { 
    //该方法将类的数据写入外部提供的Parcel中.即打包需要传递的数据到Parcel容器保存， 
    // 以便从parcel容器获取数据 
    dest.writeString(name); 
    dest.writeInt(id); 
 
  } 
  public static final Creator<Author> CREATOR=new Creator<Author>() { 
    @Override 
    public Author createFromParcel(Parcel source) { 
      //从Parcel容器中读取传递数据值，封装成Parcelable对象返回逻辑层。 
      Author author=new Author(); 
      author.setName(source.readString()); 
      author.setId(source.readInt()); 
      return author; 
    } 
 
    @Override 
    public Author[] newArray(int size) { 
      //创建一个类型为T，长度为size的数组，仅一句话（return new T[size])即可。方法是供外部类反序列化本类数组使用。 
      return new Author[size]; 
    } 
  }; 
} 

public class Book implements Parcelable{ 
  private String title; 
  private Author author; 
  //setter & getter... 
 
  @Override 
  public int describeContents() { 
    return 0; 
  } 
 
  @Override 
  public void writeToParcel(Parcel dest, int flags) { 
    dest.writeString(title); 
    dest.writeParcelable(author,flags); 
  } 
  public static final Creator<Book> CREATOR=new Creator<Book>() { 
    @Override 
    public Book createFromParcel(Parcel source) { 
      Book book=new Book(); 
      book.setTitle(source.readString()); 
      book.setAuthor(source.<Author>readParcelable(Author.class.getClassLoader())); 
      return book; 
    } 
 
    @Override 
    public Book[] newArray(int size) { 
      return new Book[0]; 
    } 
  }; 
} 

Book book=new Book(); 
book.setTitle("Java编程思想"); 
Author author=new Author(); 
author.setId(1); 
author.setName("Bruce Eckel"); 
book.setAuthor(author); 
Intent intent=new Intent(this,SecondActivity.class); 
intent.putExtra("book",book); 
startActivity(intent); 

Book book=getIntent().getParcelableExtra("book"); 
Log.d(TAG,"book title->"+book.getTitle()); 
Log.d(TAG,"book author name->"+book.getAuthor().getName()); 

@Parcel 
 
public class Author { 
 
  int id; 
 
  String name; 
 
  //setter & getter... 
} 

@Parcel 
public class Book { 
  String title; 
  Author author; 
  //setter & getter 
} 

Book book=new Book(); 
book.setTitle("Java编程思想"); 
Author author=new Author(); 
author.setId(1); 
author.setName("Bruce Eckel"); 
book.setAuthor(author); 
Intent intent=new Intent(this,SecondActivity.class); 
intent.putExtra("book", Parcels.wrap(book)); 
startActivity(intent); 

Book book= Parcels.unwrap(getIntent().getParcelableExtra("book")); 
Log.d(TAG,"book title->"+book.getTitle()); 
Log.d(TAG,"book author name->"+book.getAuthor().getName());